The synthesis of 11-deoxy-PGE.sub.2 is described by Bagli and Bogri in Tetrahedron Letters, 1972, p. 3815. The octenol side chain in that synthesis is elaborated from a nitro methylene group introduced at the correct position on the cyclopropane ring by conjugate addition of nitro-methane. Synthesis of 11-desoxy PGE.sub.1 using conjugate addition, to 2-(6'-carbo-alkoxyhexyl)-cyclopent-2-en-1-one of a vinyl copper reagent derived from tri-n-butyl-phosphine copper iodide and 1-lithio-3-(.alpha.-ethoxy)-ethoxy-oct-1-en is described in Netherlands patent 7301094 and by Sih et al. in Tetrahedron Letters, 1972, p. 2435. Netherlands Pat. No. 7301094 also suggests that methyl or ethyl are suitable alternative substituents in the 3-position of 1-lithio-3-(.alpha.-ethoxy)-ethoxy-oct-1-ene. Corey and Beames in the Journal of the American Chemical Society, 94, p. 7210, (1972) show the conjugate addition of a vinyl copper reagent derived from 1-pentynyl copper and 1-lithio-3-(dimethyl-5-butyl-silyloxy)-oct-1-en to cyclohex-2-en-3-one, and suggest the usefulness of this vinyl copper reagent in prostaglandin synthesis. 11-Deoxy-5 and 6-dehydro prostaglandins which are unsubstituted at the 15-position have also been prepared, but by processes different from those set forth in this application. These syntheses are reported in Canadian Journal of Chemistry, 49, 1070 (1971), Offenlegungsschrift 2, 313, 868 October 4, 1973, and Journal of Organic Chemistry, 39, 2506 (1974).
The present invention provides a direct method for the total synthesis of 11-deoxy-PGE type compounds substituted in the 15-position with such groups as ethynyl and methyl.